February 17, 201214 yr comment_584987 Hey I have a Toyota corolla ae92 it has the 4afc motor I have changed the carby because a backfiring issue but still remains what else can it be? The carby is a sealed unit u can't change air or fuel mixture I have a brand new muffler on it also new plugs new leads and new rotor button and cap i need help please Report
February 17, 201214 yr Author comment_584988 Do I change the intake manifold and exhaust gaskets as well? Report
February 17, 201214 yr comment_585001 Burnt inlet valve will backfire too. When does it backfire? Idling? Accelerating? Over-run/downhill only? Report
February 18, 201214 yr comment_585103 Do a compression test and see if one of the inlet valves is leaking back into the carb. Is this a sharp explosion "BANG" back in the manifold, of more of a "cough" as it misfires? Our R31 Pintara does it just as you accelerate again after trailing the throttle, so changing gear is a common time. It just gives a little cough as the throttle opens. I don't want to look at it, the car is worth nothing really, but the cost of buying something else to replace it will be... Report
February 20, 201214 yr Author comment_585676 There is no problem with my carb no back firing coming thru there just exhaust only Report
February 20, 201214 yr comment_585679 Ignition timing can do that, give it 8-10deg advance and see if that makes a difference. Otherwise do a compression test to see if an exhaust valve is leaking. If it doesn't fire a cylinder it dumps that unburnt fuel out into the exhaust where the flame from the next cylinder fires it. So if a plug or lead or any part of the ignition circuit is missing a cylinder that might do it. Report
February 21, 201214 yr comment_585742 Do a compression test and see if one of the inlet valves is leaking back into the carb. Is this a sharp explosion "BANG" back in the manifold, of more of a "cough" as it misfires? Our R31 Pintara does it just as you accelerate again after trailing the throttle, so changing gear is a common time. It just gives a little cough as the throttle opens. I don't want to look at it, the car is worth nothing really, but the cost of buying something else to replace it will be... Twin spark CA20 Altezza?? Sorry for unrelated post. Report
February 21, 201214 yr comment_585763 yep- Although I do have both coils firing at the same time. Interestingly, we checked plugs recently and the driver's side 4 were beautifully clean (the main ones) and the passenger's were black and crappy. So although they fire together the secondarys are not in a place where there is a good burn. (which is why the factory fitted them I suppose!) Since August its done two trips Orange to Armidale and back, and a trip up to the Queensland border... No problems at all, except a bolt came fractionally loose in the rear suspension and caused it to creak over bumps. ..and the UJ at the diff shat itself, but hey, it was free! Report
February 21, 201214 yr comment_585765 Can't complain about free cars! A friend of mine had one for a daily. Picked it up for 250 bucks i think. He just slapped some rego on it and bashed it around. He ended up sledging out in the wet, mounting a curb and landing on a large rock. The chassis was ALL bent up. Still drove it for months after that. The thing was a machine, just kept going and going. They run mighty lean :P Report
February 23, 201214 yr Author comment_586318 Ok so what I am going to well doing is! I paid for a new manifold carb recon emissions control hoses upper throttle cleaner helps clear cylinders I am just gonna go over bored and make sure I don't miss any thing replacing the catconverter and exhaust manifold with pacemakers should fix it Report
February 28, 201214 yr Author comment_587403 Ok I found the problem my emissions where dumping alot of its shit back in the motor so I have disconnected it and plugged it and drilled out mixture screws and cleaned carby with carby cleaner Report
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